1. Field of the Invention
The present invention relates to a flow passage switching valve, and more particularly, to a flow passage switching valve that can easily switch, for example, a plurality of flow passages.
2. Description of the Related Art
In the past, a technique disclosed in JP 8-145206 A has been known as the related art that controls the opening/closing of a valve and the opening of the valve by rotating a valve disposed in a valve chest.
A ball valve disclosed in JP 8-145206 A is adapted so that a cassette type valve element is detachably fitted and fixed to a valve box of a valve body including an inlet and an outlet for fluid on both sides thereof and a ball valve part assembled in a cylindrical body of the valve element is opened and closed by a valve stem engaged with a ball top end through the valve box and the cylindrical body. Further, a pair of seal members, which support the ball valve part so as to allow the ball valve part to be rotatable and block the flow of fluid between the ball valve part and the cylindrical body, is provided at inner positions on one opening end side and the other opening end side of the cylindrical body.